The vials of insulin you’ll use immediately don’t need to be refrigerated, says the American Diabetes Association (ADA). Modern insulin is stable for at least one month at room temperature.

In fact, you probably don’t need to carry an insulin cooler – your pocket or purse will work just fine. Just don’t leave it near any heat source or light, or in a car, which can quickly become very hot or very cold.

Unopened vials of insulin, the ADA says, can be stored in the refrigerator but never in the freezer. And don’t put the vials in the refrigerator door, the ADA says, because the jarring movements of the door may lower the activity of the insulin. Try to keep your insulin on a low shelf in the refrigerator so it doesn’t freeze.